Roughly chop the cabbage, thinly slice the onion, and cut the carrot into thin batons. If using, cut the garlic chives into 4 cm lengths and halve the baby corn.
Cut the thinly sliced pork into bite-sized pieces.
Microwave the frozen udon according to the package directions so the noodles loosen and separate. Set aside.
Heat a little oil in a large frying pan over medium-high heat. Add the pork, season with a little salt and pepper, and cook until it changes color.
Add the onion and carrot and stir-fry until they start to soften.
Add the cabbage (and baby corn and garlic chives if using) and stir-fry about 1 minute. Tear open the dashi packet and sprinkle the contents over everything with a little more salt and pepper, tossing to coat.
Add the warmed udon to the pan and mix gently.
Add the oyster sauce (or soy sauce) and toss until the noodles are evenly coated and lightly glossy. Taste and adjust.
Plate and finish with a generous shower of bonito flakes and a sprinkle of aonori. Serve immediately.
